In June, 21-year-old Richardson had won the 100 m at the US trials in Oregon and at a meet in Florida, she became the sixth-fastest woman in the world at the 100m distance, with a time of 10.72 seconds.
Marijuana is now on the World Anti-Doping Agency’s list as a prohibited substance. This positive test result can carry a ban for either one month or 2 years.
Even if Richardson receives the minimum punishment, a positive test at the trials could invalidate her victory there and cause someone who did not run as fast to step up into a higher position.
Watch as she speaks on the test result below.